/*
 *  Copyright (c) WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 *  WSO2 Inc. licenses this file to you under the Apache License,
 *  Version 2.0 (the "License"); you may not use this file except
 *  in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.wso2.balana.xacml3;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.wso2.balana.*;
import org.wso2.balana.ctx.EvaluationCtx;
import org.wso2.balana.ctx.Status;
import org.wso2.balana.TargetMatch;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Represents AllOfType in the XACML 3.0 policy schema.
 */
public class AllOfSelection {

	/**
	 * List of SubjectMatch, ResourceMatch, ActionMatch, or EnvironmentMatch
	 */
	List<TargetMatch> matches;

	/**
	 * Constructor that creates a <code>AllOfSelection</code> from components.
	 * 
	 * @param matches
	 *            a <code>List</code> of <code>TargetMatch</code> elements
	 */
	public AllOfSelection(List<TargetMatch> matches) {
		this.matches = matches;

	}

	/**
	 * creates a new <code>AllOfSelection</code> by parsing DOM node.
	 * 
	 * @param root
	 *            DOM node
	 * @param metaData
	 *            policy meta data
	 * @return <code>AllOfSelection</code>
	 * @throws ParsingException
	 *             throws, if the DOM node is invalid
	 */
	public static AllOfSelection getInstance(Node root, PolicyMetaData metaData)
			throws ParsingException {

		List<TargetMatch> targetMatches = new ArrayList<TargetMatch>();
		NodeList children = root.getChildNodes();
		for (int i = 0; i < children.getLength(); i++) {
			Node child = children.item(i);
			if ("Match".equals(child.getNodeName())) {
				targetMatches.add(TargetMatch.getInstance(child, metaData));
			}
		}

		if (targetMatches.isEmpty()) {
			throw new ParsingException("AllOf must contain at least one Match");
		}

		return new AllOfSelection(targetMatches);
	}

	/**
	 * 
	 * Determines whether this <code>AllOfSelection</code> matches the input
	 * request (whether it is applicable).
	 * 
	 * @param context
	 *            the representation of the request
	 * 
	 * @return the result of trying to match the group with the context
	 */
	public MatchResult match(EvaluationCtx context) {

		// there are specific matching elements, so prepare to iterate
		// through the list
		Iterator it = matches.iterator();
		Status firstIndeterminateStatus = null;
		MatchResult result;

		while (it.hasNext()) {
			TargetMatch targetMatch = (TargetMatch) (it.next());
			result = targetMatch.match(context);
			if (result.getResult() == MatchResult.NO_MATCH) {
				return result;
			}

			if (result.getResult() == MatchResult.INDETERMINATE) {
				if (firstIndeterminateStatus == null) {
					firstIndeterminateStatus = result.getStatus();
				}
			}
		}

		// if we got here, then none of the sub-matches passed, so
		// we have to see if we got any INDETERMINATE cases
		if (firstIndeterminateStatus == null)
			return new MatchResult(MatchResult.MATCH);
		else
			return new MatchResult(MatchResult.INDETERMINATE,
					firstIndeterminateStatus);

	}
}
